The present invention relates to a data processor, and more particularly, to a data processor used in a recording-reproducing device for a compact disc (CD) or a digital versatile disc (DVD) to perform modulation or demodulation.
An optical disc, such as a CD or a DVD, is used as a recording medium that stores a large amount of data. The CD includes a compact disc read only memory (CD-ROM), a compact disc-recordable (CD-R), and a compact disc-rewritable (CDRW). The DVD includes a digital versatile disc read only memory (DVD-ROM), a digital versatile disc-recordable (DVD-R), and a digital versatile disc-rewritable (DVD-RW).
In recent years, a recording-reproducing device compatibly used for a CD-ROM, a CD-R, a CD-RW, and a DVD-ROM has been proposed. To achieve miniaturization, such a recording-reproducing device includes a single-chip large scale integration (LSI) circuit provided with the function of a CD decoder and the function of a DVD decoder. Further, to manufacture a compact recording-reproducing device for a data writable DVD (DVD-R, DVD-RW), an LSI provided with the function of a DVD encoder is being developed.
A writable CD, such as a CD-R or a CD-RW, has a track including grooves formed in lands of the disc. The grooves are slightly wobbled in the radial direction of the CD. Information referred to as absolute time in pregroove (ATIP) is written to the grooves in accordance with the cyclic wobble changes. In a CD-R or CD-RW, the track is traced to read the ATIP information written to the grooves and obtain the absolute time information of the present track position. The absolute time information indicates a position on the disc and is used as address information for designating a write position of the recording medium. The recording-reproducing device uses a laser pickup to detect the wobble cycle and generate a wobble signal.
In a writable DVD, such as a DVD-R or a DVD-RW, areas storing address information, which is referred to as a land prepit (LPP), is provided at predetermined intervals in a track. Unlike the absolute time information of track positions in a CD, the address information of the LPP is obtained from consecutive numbers applied to each sector. The recording-reproducing device uses a laser pickup to detect the position of the LPP and generate a LPP signal.
As described above, a CD and a DVD record address information, which indicates write positions, in a different manner. Further, a CD and a DVD use different data recording formats and perform modulation in different manners. Therefore, in the prior art, the recording-reproducing device includes a data processing circuit for recording data on a CD and a separate data processing circuit for recording data on a DVD. These circuits are arranged parallel to each other and increase the circuit scale of the LSI.